Carboxymethylcellulose (CMC) is a water-soluble polymer, which is widely used in various
fields such as food additives, textiles, pharmaceuticals and cosmetics. In this study, hydrogel
was prepared from CMC by using calcium chloride as a crosslinking agent. Optimization
of the reaction was done through investigation of four different parameters which had
different percentage of CMC (w/v), percentage of calcium chloride (w/v), reaction time and
temperature. The gel content and swelling properties of the CMC hydrogel were studied.
The highest gel content was 85.33% at 7% of CMC (w/v) with 2% of calcium chloride (w/v)
in 24 hours reaction time at room temperature. The gel content increased with the increasing
concentration of CMC and CaCl2. This was due to the higher number of functional groups
of COO- that were available in more concentrated CMC which could crosslink with CaCl2
to give higher gel content. Increasing the percentage of CaCl2 will increase the electrostatic
attraction between anionic charges of polymer chains and multivalent cation (Ca2+) that
leads to increase in ionic crosslinking of CMC. The swelling properties of CMC hydrogel
showed that the optimum degree of swelling was 45.33 (g/g). The swelling capacity of the
hydrogel in water decreased with the increase of the gel content of CMC hydrogel. This
could be due to the increase in the degree of crosslinking of the CMC hydrogel.
(Kenaf fibre is a good reinforcement in fibre polymer composites due to its high strength
and elastic modulus, high stiffness, low density, low cost and eco-efficient, less health
hazards, renewability, good mechanical and thermal properties, and biodegradability. It is
traditionally used for rope, twine, fish net and sacking materials. Recently, it was observed
that kenaf fibre had huge potentials to replacing synthetic fibre in composites due to the
rising environmental and ecological issues, thus this awareness has motivated efforts for
the advancement of new innovative bio-based composites incorporating kenaf fibre for
various end-use structural applications. This paper presents an overview of the development
made so far in the area of kenaf fibre and its composites in terms of chemical and microstructural
properties, mechanical properties, dimensional stability, thermal stability, product
development and application. Some fundamental issues and suggestions for further research
in this area are also discussed.
Cogeneration systems are extensively used in Malaysia to produce power as a primary
source. However, in the event of cogeneration system failure, the customer or the client are
forced to use a redundancy to avoid power interruptions. There are two methods commonly
used as a backup in the cogeneration systems which are Generator set and public utility. In
order to choose the best redundancy for a particular cogeneration system, it is essential to
evaluate the economic benefit analysis by considering several factors such as Maximum
demand charge, installation cost and Discount interest. In the evaluation of economic
benefit, this study identifies the number of failure and associated downtime using reliability
and availability approach, and then present value method was applied. The result shows
that the usage of public utility as redundancy is beneficial if the cogeneration system
operates within five years period. However, if the cogeneration system operates more than
five years, generator set option would be a better option to minimize the total cost. This
research also addresses the effect of various factors such as installation cost, maximum
demand charge, fuel cost, discount interest rate and production capacity. In general, the
output of the research would be beneficial for the plant operator to select the appropriate
redundancy option based on the economic advantages.
Cement Kiln Dust (CKD) is a by-product generated throughout the production of Ordinary
Portland Cement (OPC). It is normally emitted to the atmosphere or converted into liquid
and subsequently drained out as effluents to landfills and wastage areas. It impacted human
health and the environment negatively. However, it can be utilized in concrete as raw
cement replacement materials due to its engineering properties which work as an alternative
binder of OPC in addition to that it has benefits in creating economic and environmental
advantages. This study aimed to modify CKD and investigate the chemical composition
of normal-CKD and modified -CKD accordingly. The term modified noted that CKD has
gone through a process of modification using heating process. The reactivity property of
CKD was investigated using pH analysis. Then, mix proportions of different percentage
of normal-CKD and modified -CKD were developed to study the addition effects on
the compressive and flexural strength for different curing period. The trend of strength
development over the addition of CKD was also analyzed. OPC was replaced by CKD at
0% and successively increased by 10% to 100% through binder weight (OPC). A fixed
amount of water to binder (W/B) with a ratio of 0.45 was used for all hybrids. The mixes
were formed into the specimen and tested for compressive strength and flexural strength at
7, 14 and 28 curing days. The medium particle size of CKD used was less than 10μm. The
results of compressive and flexural strength showed that modified-CKD resulted in better
properties and 10% replacement showed
the maximum values of compressive and
flexural strength as a result considered best
percentage replacement in agreement with
its noteworthy results.
This review is aimed to present an in-depth review of several methodologies on magnetic
water treatment (MWT) that are employed as scale treatment in water pipeline and to
critically discuss each method in order to determine the best outcome of MWT. The
magnetically assisted water in pipeline in various applications are presented, argued and
best variables are listed according to the performance of each MWT. The advantages and
limitations of MWT are discussed and the main outcome from the review summarize the
best method in MWT, especially in effectiveness of treating scale in terms of sustained
environment benefits. Magnetic field application in water treatment has the potential to
improve the water pipeline performance and lifetime. The application is also significant in
controlling the growth of scale in upcoming system. Both of these benefits lead to healthier
water treatment, increasing and maintaining the lifetime and performance of water system.
This research was conducted to investigate the compaction performance and mechanical
strength of compacted urea fertilizer in unlubricated and lubricated die systems. The
ground urea 46% N fertilizer was compacted in a 13 mm flat-face cylindrical die set in
both unlubricated and lubricated die systems with vegetable fatty acids and magnesium
stearate as lubricants at various compaction stresses to produce urea fertilizer tablets. In
conclusion, a lubricated die system reduces the frictional effects during the production of
urea fertilizer tablets and also produces a mechanically stronger urea fertilizer tablet than
those produced in an unlubricated die system. In addition, the vegetable fatty acids and
magnesium stearate lubricants are found to improve the compaction performance of urea
fertilizer tablet as well as its mechanical strength.
Competition for limited available water for crop production is an ever-increasing issue for
farmers due to increasing demand of irrigation water worldwide. Due to high energy cost
in operating pressurized irrigation systems, energy-efficient low-pressure wick irrigation
systems can play important roles for smallholder greenhouse crop production by ensuring
higher water use efficiency than most traditional approaches. The objectives of this study
were to investigate HYDRUS 2D-simulated water distribution patterns in soil and soilless
growing media, and to evaluate water balance in these media under capillary wick irrigation
system. To accomplish these objectives, eggplants (Solanum melongena L.) were grown
in potted peatgro and sandy clay loam in a greenhouse experiment, water distribution was
simulated by using HYDRUS 2D software package and compared with the measured
values, and water uptake by the plant roots was determined for water balance calculation.
The wetting pattern was found axially symmetric in both growing media (peatgro and
soil) under the wick emitters. The simulated
water distribution in both growing media
revealed dependency of spatial extent of the
wetted zone on water application period and
hydraulic properties of the media. The mean
absolute error (MAE) in water content over
depth varied from 0.04 to 0.10 m3 m−3 and the root mean square error (RMSE) varied from 0.04 to 0.11 m3 m−3. Deviations between the
measured and simulated water contents in the peatgro medium were larger over depth than
over lateral distance. In contrast, the model criteria matched well for the sandy clay loam
and provided MAE of 0.01 to 0.02 m3 m−3 and RMSE of 0.01 to 0.03 m3 m−3, indicating
good agreement between the measured and simulated water contents.
Palm oil (PO) and fully hydrogenated palm oil (FHPO) were subjected to enzymatic
interesterification using 9.5% of TLIM Lipozyme. The optimum condition for this process
occurred at 62.75°C, with reaction time 172.50 minutes with the ratio of 1:1 for palm oil to
hydrogenated palm oil respectively. The Palmitoyl-Oleoyl-Stereoyl (POS) yield obtained
was approximately 15%. Product was subsequently subjected to a fractionation process
at various cooling temperatures and reaction time. At 34°C, POS achieved was at the
highest level which was approximately 31% after 12 hours cooling process. The study of
physiochemical properties of the Cocoa butter Equivalent (CBE) fat was determined for the
purpose of characterization identification. The properties identified were solid fat content,
slip melting point (SMP) and iodine value (IV). The IV and SMP values obtained were
44.30 and 29°C respectively. However, CBE produced almost 0% of Solid Fat Content
(SFC) at 30°C. Apart from the high yield of POS, the physicochemical characteristics
showed significant compatibility with that of CB. In addition, the crystal polymorph of
CBE 34 physicochemical characteristics of CBE34 (β′+β) was similar to CBE. Hence, from
this study, CBE 34 is recommended for utilization in the confectionery industry as CBE.
Doppler ultrasound is used in obstetrics and gynecology fields to serve as the complement
mode in the standard prenatal scan. It aids in investigating fetus blood flow in expectant
mothers’ wombs, usually those who come with pregnancy complications. In the conventional
ultrasound beam, the heat produced by attenuation is distributed over the area. However, the
Doppler ultrasound beam is focused at only one point. This leads the heat to accumulate at
that particular area and hence there is an increase in the temperature. Heat is considered as
a teratogen in pregnancy, whereby an increase in the fetal temperature can be fatal to the
fetus. Studies have found that Doppler mode is associated with higher acoustic output as
compared to the conventional two-dimensional (2D) ultrasound mode. Several studies done
on animals have ruled out the evidence of Doppler ultrasound bioeffects. This narrative
review only discusses the thermally induced effect of ultrasound by using Doppler mode.
This study reviews prior studies with keywords such as Doppler ultrasound, bioeffects,
heating effects, rabbit, and pregnancy. Earlier studies noted that the risk of thermal effects
increased with the increase of exposure time. However, Doppler ultrasound wave inducing
fetal hyperthermia is not the main reason for
causing adverse neonatal outcomes without
taking into account other external factors.
Therefore, it is essential for the practitioners
to adopt and adapt the concept of ‘as low as
reasonably achievable’ (ALARA) to avoid
any subtle adverse effects.
Notably in the construction industry, procurement is evidently important and cannot be played down because it constitutes every phase of a project delivery system. The low-bid system has remained the most popular procurement system globally. In Nigeria, it lacks transparency and accountability. Therefore, the Nigerian Procurement system has shown a need to be stabilised by shifting risk and control to the expert who has the duty to act in the client’s best interest by adopting “Best Value Performance Information Procurement System (BVPIPS)” in contractor selection. This paper aims at identifying factors that can hinder the implementation of this innovative procurement system and their relative influence. A total 314 questionnaires were distributed to 5 construction industry professionals in Nigeria they are: Architects, Quantity Surveyors, Civil Engineers, Builders and Services Engineers. The data collected were presented and analysed using: cross tabulation, exploratory factor analysis and mean score ranking using Statistical Package for Social Sciences (SPSS) version 24 and Microsoft Excel respectively. Likert scaling was used to measure the level of agreement of the respondents. The paper found out that the social factor, political factor, procurement environment factors and the cultural factor in the construction industry ranked 1, 2, 3 and 4 respectively and which factors have a very strong relative influence on hindering the implementation of BVPIPS in the Nigerian construction industry. The implication of this study is, to help construction practitioners, researchers, academics, industry players, and other stakeholders to look into the significant issues that can hinder the implementation of PIPS in Nigeria and make better the delivery of projects in the construction industry. Therefore, these factors identified should be considered and precautionary measures taken when implementing BVPIPS in the Nigerian construction industry so as to accommodate innovative approaches such as BVPIPS to improve project delivery in Nigeria.
In this study, papaya (Carica papaya) peel was dried using convection oven and microwave drying methods to investigate the drying kinetics and the drying behavior in the attempt to search for a feasible way to utilize waste peel. Three different drying temperatures (45, 55, and 65 oC) and microwave powers (250, 440, and 600 W) were applied to dry the papaya peel, wherein the drying data were fitted into the following seven drying kinetic models: Lewis, Page, Modified Page, Henderson and Pabis, Logarithmic, Two-Term, and Approximation of Diffusion models. The study outcomes indicated that the Page model emerged as the best fitted model for oven drying of papaya peels with the highest coefficient of determination (R2) value (0.994-0.996) for all the three temperatures. As for microwave drying, the Approximation of Diffusion model exhibited the best fit owing to the highest R2 value (0.996-0.999) for all the three powers. The effective moisture diffusivity values for convection oven and microwave drying methods ranged from 6.65 x 10-08 to 4.35 x 10-07 and from 2.43 x 10-07 to 6.67 x 10-07, respectively. Additionally, the activation energy values were recorded at 61.301 kJ/mol and 46.621 W/g for oven and microwave drying methods, respectively.
The breast cancer automatic diagnosis is a critical real world medical challenge. This study proposes a classifying cancer tumor method based on their gene expression signatures to specific diagnostic categories. The developed neural network model holds promise for patients, surgeons, and radiologists, providing them with information, which was only available using biopsy. This significantly reduces the number of pointless surgical procedures. This study utilizes Wave Atom Transform as feature extraction method, and Back Propagation Algorithm to classify cancer into pre-defined classes. The proposed model provides automatic detection with a high level of accuracy (90%).
Waste rocks are a non-economical by-product of mining operations, which can lock up carbon dioxide into a carbonate form and thereby help reduce greenhouse gases emissions. The aims of this research are to determine the mineral and chemical composition of the sedimentary waste rocks of gold mines and to classify the potential of silicate minerals to be a feedstock for carbonation mineralization. The sampling was undertaken at the Selinsing gold mine, where waste rocks were collected from the waste dump, stockpiles, the borrow pit, and the main pit. The mineralogical and chemical component of the sedimentary waste rocks were explored using X-ray diffraction and energy dispersive X-ray spectroscopy. The findings indicated that the presence of divalent cations, of 55.12% for CaO, 9.09% for MgO, and 16.24% for Fe2O3 from gold mine waste, capable of sequestering carbon dioxide into calcium, magnesium and iron carbonates, respectively, through carbonation of mineral. The domination of silicate minerals such as quartz, muscovite, kaolinite, chlorite, albite, and carbonate minerals such as calcite, have been found to be widespread in sedimentary waste rocks. However, the natural silicates (chlorite, muscovite) and carbonates (calcite) are potential minerals which can be consumed as feedstock for carbonation processes because they contain the magnesium, iron, and calcium elements which can form stable carbonates in the presence of carbon dioxide. The mineralogy and chemical composition of sedimentary waste rocks from the Selinsing gold mine provides a better understanding of the future carbonation reaction to sequester more carbon dioxide in response to climate change.
Greywater traditionally receives the least attention compared to other aspects of environmental sanitation. In Malaysia, most of village houses discharged lots of significant portion of greywater into stream without any treatment. Laundry Greywater (LGW) is one of the largest portion of greywater that has been directly discharged to the stream. The aim of this study was to identify the physical and chemical characteristic of laundry greywater quality from the houses and also to evaluate the efficiency of using ceramic waste coarse aggregate filtration for LGW treatment. The effectiveness of the treatment systems was optimized with different Hydraulic Retention Time (HRT) and volume of samples by using Response Surface Methodology (RSM). The samples were taken from the direct discharge point of the laundry greywater at two houses. The results revealed that the efficiency of designed filtration system depended on HRT and volume of samples. The highest Chemical Oxygen Demand (COD) removal from 1 L of LGW and after 3 hrs was 43.31%, while the highest removal of orthophosphate (PO4) (100%) and sodium (Na) (27.48%) were recorded with 2 L and after 2 hrs. It can be concluded that the ceramic waste coarse aggregate filtration was effective in reducing the pollutants in the LGW before the final disposal into the environment.
This paper highlights basic data collected over the 7 years and 8 years of establishment of the marine turtle hatchery projects in Pulau Rusukan Besar Marine Park Centre (PRBMPC), Federal Territory of Labuan and Pulau Redang Marine Park Centre (PRMPC), Terengganu; Malaysia, respectively. Compiled data were taken from year 2010 until 2017. The within and between season patterns in terms of nest number of the green (Chelonia mydas) and hawksbill (Eretmochelys imbricate) turtles were shown. The population of marine turtles were estimated from the number of nests laid. Total annual nests were used as a crude index of female turtle abundance. Green turtles accounted for 96.18% (1,233 nests laid) of the total nesting recorded while hawksbills accounted for the remaining 3.82% (49 nests laid) in the PRMPC. However, in the PRBMPC 23.58 % (29 nests laid) and 76.42% (94 nests laid) were recorded respectively for the green and hawksbill turtle. 100 % of the nest laid have been incubated using the ex-situ conservation method with the production of 103,929 and 23,558 live green and hawksbill turtle hatchlings respectively. The 8-year average hatching and emergence success rates for green turtles and hawksbills were 87.11 and 88.33%, and 91.56 and 90.69% respectively. This paper provides important information that is fundamental for the understanding of population status to ensure effective conservation measures and management of marine turtles at both marine parks.
Oil spill introduces hydrocarbons into the marine environment and forms oil slicks, which aggregate with other debris to form tarballs. Tarballs are composed of toxic hydrocarbons, which persist in the environment, causing economic and ecological damages. This work studied the isolation and optimization of diesel-oil biodegradation by an indigenous bacterium, identified by 16S rRNA gene sequence analysis, in tarball. An experimental methodology using a Taguchi orthogonal array was applied to optimize the effects of diesel concentration, salinity, nitrate concentration, pH, temperature, agitation speed and time. An isolated bacterium identified as Cellulosimicrobium cellulans removed 88.4% of diesel oil under optimized conditions, where initial diesel-oil concentration was 5% (v/v), NaCl concentration was 20 gL-1 and NH4NO3 concentration was 2 gL-1 in Minimal Salt Media at pH 7, 40oC and 100 revolutions per minute for 5 days. Tarballs harbor hydrocarbon-degrading C. cellulans that can be used under optimized conditions to design an effective oil spill bioremediation technique for mitigating oil pollution.
Diuron has been substantially used in different parts of the world as an herbicide and as a bioactive ingredient in antifouling paint. However, knowledge on the toxicity of Diuron that could adversely affect non-targeted aquatic organisms, especially fish; is still deficient. Therefore, this study was conducted to determine the possible sublethal effects of phenylurea herbicide Diuron at the cellular level of the liver and kidneys of an adult Javanese medaka (Oryzias javanicus), which has been used as the novel model organism. In the present study, histological assessment was carried out using the hematoxylin and eosin (H&E) staining protocol where the samples were preserved in 10% buffered formalin and sectioned into 5 μm thickness. The 210 samples used contained a range of Diuron concentrations comprising 1 μg/L, 50μg/L, 100 μg/L, 500 μg/L and 1000 μg/L; which also included the control treatments. Semi quantitative analysis revealed that liver and kidney tissues exposed at higher concentrations (500 μg/L and 1000 μg/L) showed significantly moderate to severe deformities and mild lesion alterations were already shown even at a lower concentration of Diuron exposure (1.0 μg/L), as compared to the control treatment of dechlorinated water (p
High concentration of iron (Fe) levels (above 1.0 mg/L) in water causes bad taste, staining and deposition in pipes and results in high turbidity in water supplies. Existing treatment technologies (which have been conventionally applied to remove Fe ions), are expensive and cause toxic sludge production. A set of experiments was carried out to evaluate the Fe uptake potential of spent coffee grounds by conducting batch tests in an aqueous solution through a biosorption process. Batch sorption studies were conducted based on pH, contact time, adsorbent dosage and adsorbent particle size. In addition, initial metal concentration was investigated. Flame atomic adsorption spectroscopy analysis revealed that the maximum adsorption recorded was 0.470 mg g-1 by using 0.30 g of 210-355 μm coffee with the maximum uptake percentage of Fe (92.9%) for 60 minutes at pH 4. Adsorption behavior of Fe ions on a surface of coffee grounds was well-interpreted by Langmuir model (R2 = 0.999). A kinetic study indicated that the Fe ions uptake was wellfitted by the pseudo second-order reaction model with good correlation (R2 = 0.993). The study offered an affirmative answer to the hypothesis of reusing eco-friendly and low-cost coffee grounds for removal of Fe ions from polluted waters.
This study attempts to develop a soil moisture measurement system with a monopole antenna sensor, mini-VNA Tiny and a mobile phone respectively. The mini-VNA Tiny is a compact vector network analyzer (VNA) with a USB connection to a smartphone or a tablet. There are 17 sets of data which have been collected from 15 different spots with varying soil moisture content. The actual moisture content on site was collected from TRIME-PICO 64/32 sensor. Upon collection, it was necessary to calibrate the resistance obtained from the mini-VNA between 1 MHz and 3 GHz. The data obtained from the study shows that the resonances of the antenna resistance shift to the left on the frequency spectrum as moisture content increases. A linear model relating the resistance and actual moisture content was developed from this study with coefficient of determination (R2) value of 0.723 at 13 MHz. This value is much less than the anticipated R2 = 0.95 for accurate measurement of soil moisture with monopole antenna at microwave frequency. This could be due to the 0.60 cm thickness of the monopole antenna which may not be suited for soil moisture measurement. Nonetheless, this study demonstrates the potential application of an inexpensive and portable mini-VNA Tiny and smartphone system for sensing applications.
Field surveys of the 2011 Tohoku Tsunami reported massive failures of many seawalls and coastal barriers. The massive damages are vivid evidence that there are flaws in the design of seawalls and barriers. With this as the background, a sequence of laboratory experiments using dam-break waves was performed to simulate the interactions between the tsunami-like bore flow and vertical seawall as well as to measure the bore-induced pressures and to estimate forces exerted on the vertical seawall model. The experimental result revealed that the maximum pressure (approximately 8 kPa) exerted on the vertical seawall was measured at the lowest pressure sensor location. Experimental data were used to re-examine the relevant empirical formulae found in the literature. The obtained results could be useful for calibrating mathematical and numerical models as well as for future research concerning the design of tsunami barriers.